CHICAGO -- Weather watches and warnings were up in numerous northern and eastern U.S. states Tuesday as a winter storm that has killed at least 17 people moved east.

The majority of the deaths were associated with road accidents as freezing rain made driving conditions treacherous Monday in the Central Plains, AccuWeather reported.

At Chicago's O'Hare International Airport, at least 100 flights were canceled Monday and delays averaged 45 minutes and the Chicago Tribune quoted forecasters as saying the city was under a freezing rain advisory until midnight Tuesday.

Because of heavy ice buildup on power lines and tree branches that fell on them, as many as 600,000 homes and businesses were without power in Oklahoma and south central Kansas, The Kansas City (Mo.) Star reported.

In Oklahoma, more than 500,000 customers were also without power, The Oklahoman reported.

Boston Medical Center's emergency room reported it had treated more than 10 serious injuries caused by falls on icy streets on Monday, the Boston Globe said.

Tuesday morning, the St. Louis Post-Dispatch said dense fog caused delays at Lambert St. Louis International Airport.

AccuWeather said temperatures in Pittsburgh and Washington would climb into the 50s Tuesday, about 10 degrees above average for both cities, also bringing fog.